Your browser doesn't support javascript.
Show: 20 | 50 | 100
Results 1 - 20 de 23
Filter
1.
Lancet ; 399(10329): 1070-1078, 2022 03 12.
Article in English | MEDLINE | ID: covidwho-1735071

ABSTRACT

BACKGROUND: Transmission of SARS-CoV-2 from humans to other mammals, including pet animals, has been reported. However, with the exception of farmed mink, there is no previous evidence that these infected animals can infect humans, resulting in sustained human-to-human transmission. Following a confirmed SARS-CoV-2 infection of a pet shop worker, animals in the shop and the warehouse supplying it were tested for evidence of SARS-CoV-2 infection. METHODS: In this case study, viral swabs and blood samples were collected from animals in a pet shop and its corresponding warehouse in Hong Kong. Nasal swab or saliva samples from human COVID-19 patients epidemiologically linked to the pet shop and from subsequent local cases confirmed to be infected by SARS-CoV-2 delta variant were collected. Oral swabs were tested by quantitative RT-PCR (RT-qPCR) for SARS-CoV-2 and blood samples were serologically tested by a surrogate virus neutralisation test and plaque reduction neutralisation test. The SARS-CoV-2 RT-qPCR positive samples were sequenced by next generation viral full genome sequencing using the ISeq sequencing platform (Illumina), and the viral genomes were phylogenetically analysed. FINDINGS: Eight (50%) of 16 individually tested Syrian hamsters in the pet shop and seven (58%) of 12 Syrian hamsters in the corresponding warehouse were positive for SARS-CoV-2 infection in RT-qPCR or serological tests. None of the dwarf hamsters (n=75), rabbits (n=246), guinea pigs (n=66), chinchillas (n=116), and mice (n=2) were confirmed positive for SARS-CoV-2 in RT-qPCR tests. SARS-CoV-2 viral genomes deduced from human and hamster cases in this incident all belong to the delta variant of concern (AY.127) that had not been circulating locally before this outbreak. The viral genomes obtained from hamsters were phylogenetically related with some sequence heterogeneity. Phylogenetic dating suggests infection in these hamsters occurred around Oct 14, 2021 (95% CI Sept 15 to Nov 9, 2021). Multiple zoonotic transmission events to humans were detected, leading to onward human-to-human transmission. INTERPRETATION: Pet hamsters can be naturally infected with SARS-CoV-2. The virus can circulate among hamsters and lead to human infections. Both genetic and epidemiological results strongly suggest that there was more than one hamster-to-human transmission event in this study. This incident also led to onward human transmission. Importation of SARS-CoV-2-infected hamsters was a likely source of this outbreak. FUNDING: US National Institutes of Health, Research Grants Council of Hong Kong, Food and Health Bureau, and InnoHK.


Subject(s)
COVID-19/veterinary , Cricetinae/virology , SARS-CoV-2 , Viral Zoonoses/transmission , Adult , Animals , COVID-19/epidemiology , COVID-19/transmission , COVID-19 Nucleic Acid Testing , Child , Disease Outbreaks , Female , Hong Kong/epidemiology , Humans , Male , Pets/virology , Phylogeny
2.
SSRN;
Preprint in English | SSRN | ID: ppcovidwho-326533

ABSTRACT

Background: Transmission of SARS-CoV-2 from humans to other mammals, including pet animals, has been reported. However, with the exception of farmed mink, there is no previous documentation that these infected animals can infect humans, nor of further onward spread among humans. Following a confirmed SARS-CoV-2 infection of a pet store worker, animals in the store and the warehouse supplying it were tested for evidence of SARS-CoV-2 infection. Methods: Viral swabs and blood samples from pet animals were collected in a pet shop and the warehouse supplying it and tested by SARS-CoV-2 RT-PCR and serological assays, respectively. SARS-CoV-2 RT-PCR positive samples were studied by full genome sequencing analysis. Findings: Over 50% of individually tested Syrian hamsters in the pet shop (8/16) and warehouse (7/12) were positive for SARS-CoV-2 infection in RT-PCR or serological tests. None of dwarf hamsters (n=77), rabbits (n=246), Guinea pigs (n=66), chinchilla (n=116) and mice (n=2) were confirmed positive in RT-PCR tests. SARS-CoV-2 viral genomes deduced from human and hamster cases in this incident all belong to Delta variant of concern (AY.127) that had not been circulating locally prior. These sequences are highly similar, but distinct. The viral genomes obtained from hamsters are phylogenetically related with some sequence heterogeneity and phylogenetic dating suggest infection in these hamsters occurred around 21 November 2021. Two separate transmission events to humans are documented, one leading to onward household spread. Interpretation: Pet hamsters can be naturally infected in “real-life” settings. The virus can circulate within hamsters and lead to human infections. Both genetic and epidemiological results strongly suggest that there were two independent hamster-to-human transmission and that such events can lead to onward human transmission. Importation of infected hamsters was the most likely source of virus infection.

3.
EuropePMC; 2020.
Preprint in English | EuropePMC | ID: ppcovidwho-321486

ABSTRACT

A pandemic caused by the novel SARS-CoV-2 virus with high nucleotide identity to SARS-CoV and SARS-related coronaviruses detected in horseshoe bats is spreading across the world and impacting the healthcare systems and global economy 1,2 . A suitable small animal model is urgently needed to support the development of vaccines and antiviral treatments against the SARS-CoV-2 virus. We report the pathogenesis and transmissibility of the SARS-CoV-2 in the golden Syrian hamster model. The SARS-CoV-2 virus replicated in the epithelial cells of respiratory and gastrointestinal tracts. Immunohistochemistry demonstrated viral antigens in the areas of lung consolidation on day 2 and 5 post- inoculation, followed by rapid viral clearance and tissue repairing on day 7. Viral antigen was also detected in the epithelial cells of duodenum without apparent inflammatory response on day 2. Notably, we observed that the SARS-CoV-2 virus can be transmitted efficiently from the inoculated hamsters to co-housed naïve contact hamsters. The inoculated hamsters and naturally-infected hamsters lost greater than 10% of the body weight, and all animals recovered with the detection of neutralizing antibodies within 14 days. Our results suggest that SARS-CoV-2 infection in golden Syrian hamsters resemble features found in human patients with mild infections.Authors Sin Fun Sia, Li-Meng Yan, and Alex WH Chin contributed equally to this work.

4.
EuropePMC; 2020.
Preprint in English | EuropePMC | ID: ppcovidwho-315123

ABSTRACT

There are few studies describing the presence of respiratory viruses in respiratory droplets and aerosols in the exhaled breath of infected persons, and the efficacy of facemasks as a source control to prevent respiratory virus transmission. Here, we recruited children and adults with acute respiratory illness and collected respiratory droplets and aerosols, with and without surgical facemasks. We identified human coronaviruses, influenza virus and rhinovirus from both respiratory droplets and aerosols. Surgical face masks reduced detection of coronavirus RNA in both respiratory droplets and aerosols, but only respiratory droplets and not aerosols for influenza virus RNA. Our results provide mechanistic evidence that surgical facemasks could prevent transmission of human coronavirus and influenza virus infections if worn by symptomatic individuals.Authors Donald K Milton and Benjamin J Cowling are joint senior authors.

6.
Open forum infectious diseases ; 8(Suppl 1):S80-S81, 2021.
Article in English | EuropePMC | ID: covidwho-1564873

ABSTRACT

Background Using a computational approach, NL-CVX1 was developed by Neoleukin Therapeutics, Inc. to create a de novo protein that both blocks SARS-CoV-2 infection and is highly resilient to viral escape. In this study we evaluated the efficacy of NL-CVX1 against variants of the original SARS-CoV-2 strain, including important viral variants of concern (VOC) such as B.1.1.7, B.1.351, and P.1. Methods The relative binding affinity of NL-CVX1 to the SARS-CoV-2 viral spike protein of VOC was measured using biolayer interferometry (Octet). A competitive ELISA measured the ability of NL-CVX1 to compete with hACE2 for binding to the receptor binding domain (RBD) of the SARS-CoV-2 S protein from the original strain and VOC. The activity of NL-CVX1 in preventing viral infection was assessed by evaluating the cytopathic effects (CPE) of SARS-CoV-2 in a transmembrane protease, serine 2-expressing Vero E6 cell line (Vero E6/TMPRSS2) and determining the viral load using quantitative real-time reverse transcriptase polymerase chain reaction in infected cells. A K18hACE2 mouse model of SARS CoV-2 infection was used to study the dose-response of NL-CVX1 anti-viral activity in vivo. Results NL-CVX1 binds the RBD of different VOC of SARS-CoV-2 at low nanomolar concentrations (Fig 1;Kd < 1-~5 nM). When competing with hACE2, NL-CVX1 achieved 100% inhibition against hACE2 binding to the RBD of different VOC with IC50s values ranging from 0.7-53 nM (Fig 2). NL-CVX1 neutralized the B.1.1.7 variant as efficiently as the original strain in Vero E6/TMPRSS2 cells, with EC50 values of 16 nM and 101.2 nM, respectively (Fig 3). In mice, we found that a single intranasal dose of 100 µg NL-CVX1 prevented clinically significant SARS-CoV-2 infection and protected mice from succumbing to infection. Results from additional in vitro and in vivo experiments to be conducted this summer will be presented. Figure 1. NL-CVX1 binds the RBD from multiple strains of SARS-CoV-2 at low nanomolar concentrations. Figure 2. NL-CVX1 achieves 100% inhibition against all strains tested, including SARS-CoV-2 VOC. Figure 3. NL-CVX1 neutralizes the B.1.1.7 variant as efficiently as the original SARS-CoV-2 strain. Conclusion In vitro and in vivo data (Fig 4) demonstrate that NL-CVX1 is a promising drug candidate for the prevention and treatment of COVID-19. As a hACE2 mimetic, it is resilient to antibody escape mutations found in SARS-CoV-2 VOC. NL-CVX1 further demonstrates the power and utility of de novo protein design for developing proteins as human therapeutics. Figure 4. NL-CVX1 is effective in preventing clinically significant SARS-CoV-2 viral infection in a K18hACE2 mouse model. Disclosures Matthew Walker, PhD, Neoleukin Therapeutics, Inc. (Employee, Other Financial or Material Support, Ownership options and stock.) Laurie Tatalick, DVM, PhD, DACVP, Neoleukin Therapeutics, Inc. (Consultant, Other Financial or Material Support, Ownership options and stock.) Marianne Riley, BS, Neoleukin Therapeutics, Inc. (Employee, Other Financial or Material Support, Ownership options and stock.) Kevin Yu, BS, MS, Neoleukin Therapeutics, Inc. (Employee, Other Financial or Material Support, Ownership options and stock.) Luis M. Blancas-Mejia, PhD, Neoleukin Therapeutics, Inc. (Employee, Other Financial or Material Support, Ownership options and stock.) Daniel-Adriano Silva, PhD, Neoleukin Therapeutics, Inc. (Advisor or Review Panel member, Other Financial or Material Support, Ownership of Neoleukin options and stock) David Shoultz, PhD, MBA, Neoleukin Therapeutics, Inc. (Employee, Other Financial or Material Support, Ownership options and stock.) Goncalo Bernardes, PhD, Neoleukin Therapeutics, Inc. (Consultant, Advisor or Review Panel member, Shareholder) Hui-Ling Yen, PhD, Neoleukin Therapeutics, Inc. (Grant/Research Support)Saiba AG (Other Financial or Material Support, Received donation from Saiba AG)

7.
J Hazard Mater ; 425: 128051, 2022 03 05.
Article in English | MEDLINE | ID: covidwho-1561920

ABSTRACT

The number of people infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continues to increase worldwide, but despite extensive research, there remains significant uncertainty about the predominant routes of SARS-CoV-2 transmission. We conducted a mechanistic modeling and calculated the exposure dose and infection risk of each passenger in a two-bus COVID-19 outbreak in Hunan province, China. This outbreak originated from a single pre-symptomatic index case. Some human behavioral data related to exposure including boarding and alighting time of some passengers and seating position and mask wearing of all passengers were obtained from the available closed-circuit television images/clips and/or questionnaire survey. Least-squares fitting was performed to explore the effect of effective viral load on transmission risk, and the most likely quanta generation rate was also estimated. This study reveals the leading role of airborne SARS-CoV-2 transmission and negligible role of fomite transmission in a poorly ventilated indoor environment, highlighting the need for more targeted interventions in such environments. The quanta generation rate of the index case differed by a factor of 1.8 on the two buses and transmission occurred in the afternoon of the same day, indicating a time-varying effective viral load within a short period of five hours.


Subject(s)
Air Microbiology , COVID-19 , Fomites/virology , Motor Vehicles , SARS-CoV-2 , COVID-19/transmission , Disease Outbreaks , Humans
8.
[Unspecified Source]; 2020.
Preprint in English | [Unspecified Source] | ID: ppcovidwho-292778

ABSTRACT

There is an urgent need for the ability to rapidly develop effective countermeasures for emerging biological threats, such as the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that causes the ongoing coronavirus disease 2019 (COVID-19) pandemic. We have developed a generalized computational design strategy to rapidly engineer de novo proteins that precisely recapitulate the protein surface targeted by biological agents, like viruses, to gain entry into cells. The designed proteins act as decoys that block cellular entry and aim to be resilient to viral mutational escape. Using our novel platform, in less than ten weeks, we engineered, validated, and optimized de novo protein decoys of human angiotensin-converting enzyme 2 (hACE2), the membrane-associated protein that SARS-CoV-2 exploits to infect cells. Our optimized designs are hyperstable de novo proteins (∼18-37 kDa), have high affinity for the SARS-CoV-2 receptor binding domain (RBD) and can potently inhibit the virus infection and replication in vitro. Future refinements to our strategy can enable the rapid development of other therapeutic de novo protein decoys, not limited to neutralizing viruses, but to combat any agent that explicitly interacts with cell surface proteins to cause disease.

9.
mBio ; 12(5): e0239521, 2021 10 26.
Article in English | MEDLINE | ID: covidwho-1406605

ABSTRACT

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein is the main target for neutralizing antibodies. These antibodies can be elicited through immunization or passively transferred as therapeutics in the form of convalescent-phase sera or monoclonal antibodies (MAbs). Potently neutralizing antibodies are expected to confer protection; however, it is unclear whether weakly neutralizing antibodies contribute to protection. Also, their mechanism of action in vivo is incompletely understood. Here, we demonstrate that 2B04, an antibody with an ultrapotent neutralizing activity (50% inhibitory concentration [IC50] of 0.04 µg/ml), protects hamsters against SARS-CoV-2 in a prophylactic and therapeutic infection model. Protection is associated with reduced weight loss and viral loads in nasal turbinates and lungs after challenge. MAb 2B04 also blocked aerosol transmission of the virus to naive contacts. We next examined three additional MAbs (2C02, 2C03, and 2E06), recognizing distinct epitopes within the receptor binding domain of spike protein that possess either minimal (2C02 and 2E06, IC50 > 20 µg/ml) or weak (2C03, IC50 of 5 µg/ml) virus neutralization capacity in vitro. Only 2C03 protected Syrian hamsters from weight loss and reduced lung viral load after SARS-CoV-2 infection. Finally, we demonstrated that Fc-Fc receptor interactions were not required for protection when 2B04 and 2C03 were administered prophylactically. These findings inform the mechanism of protection and support the rational development of antibody-mediated protection against SARS-CoV-2 infections. IMPORTANCE The ongoing coronavirus disease 2019 (COVID-19) pandemic, caused by SARS-CoV-2, has resulted in the loss of millions of lives. Safe and effective vaccines are considered the ultimate remedy for the global social and economic disruption caused by the pandemic. However, a thorough understanding of the immune correlates of protection against this virus is lacking. Here, we characterized four different monoclonal antibodies and evaluated their ability to prevent or treat SARS-CoV-2 infection in Syrian hamsters. These antibodies varied in their ability to neutralize the virus in vitro. Prophylactic administration of potent and weakly neutralizing antibodies protected against SARS-CoV-2 infection, and this effect was Fc receptor independent. The potent neutralizing antibody also had therapeutic efficacy and eliminated onward aerosol transmission. In contrast, minimally neutralizing antibodies provided no protection against infection with SARS-CoV-2 in Syrian hamsters. Combined, these studies highlight the significance of weakly neutralizing antibodies in the protection against SARS-CoV-2 infection and associated disease.


Subject(s)
Antibodies, Monoclonal/metabolism , Antibodies, Neutralizing/metabolism , COVID-19/metabolism , Receptors, Fc/metabolism , Spike Glycoprotein, Coronavirus/metabolism , Animals , COVID-19/prevention & control , Cricetinae , Male , Mesocricetus , Protein Binding
11.
Nature ; 583(7818): 834-838, 2020 07.
Article in English | MEDLINE | ID: covidwho-1387423

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a novel coronavirus with high nucleotide identity to SARS-CoV and to SARS-related coronaviruses that have been detected in horseshoe bats, has spread across the world and had a global effect on healthcare systems and economies1,2. A suitable small animal model is needed to support the development of vaccines and therapies. Here we report the pathogenesis and transmissibility of SARS-CoV-2 in golden (Syrian) hamsters (Mesocricetus auratus). Immunohistochemistry assay demonstrated the presence of viral antigens in nasal mucosa, bronchial epithelial cells and areas of lung consolidation on days 2 and 5 after inoculation with SARS-CoV-2, followed by rapid viral clearance and pneumocyte hyperplasia at 7 days after inoculation. We also found viral antigens in epithelial cells of the duodenum, and detected viral RNA in faeces. Notably, SARS-CoV-2 was transmitted efficiently from inoculated hamsters to naive hamsters by direct contact and via aerosols. Transmission via fomites in soiled cages was not as efficient. Although viral RNA was continuously detected in the nasal washes of inoculated hamsters for 14 days, the communicable period was short and correlated with the detection of infectious virus but not viral RNA. Inoculated and naturally infected hamsters showed apparent weight loss on days 6-7 post-inoculation or post-contact; all hamsters returned to their original weight within 14 days and developed neutralizing antibodies. Our results suggest that features associated with SARS-CoV-2 infection in golden hamsters resemble those found in humans with mild SARS-CoV-2 infections.


Subject(s)
Betacoronavirus/pathogenicity , Coronavirus Infections/transmission , Coronavirus Infections/virology , Disease Models, Animal , Lung/pathology , Lung/virology , Mesocricetus/virology , Pneumonia, Viral/transmission , Pneumonia, Viral/virology , Aerosols , Alveolar Epithelial Cells/pathology , Alveolar Epithelial Cells/virology , Animals , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , Antigens, Viral/immunology , Antigens, Viral/isolation & purification , Antigens, Viral/metabolism , Betacoronavirus/immunology , Betacoronavirus/isolation & purification , Betacoronavirus/metabolism , Bronchi/pathology , Bronchi/virology , COVID-19 , Coronavirus Infections/immunology , Duodenum/virology , Fomites/virology , Housing, Animal , Kidney/virology , Male , Mesocricetus/immunology , Nasal Mucosa/virology , Pandemics , Pneumonia, Viral/immunology , RNA, Viral/analysis , SARS-CoV-2 , Viral Load , Weight Loss
12.
Vet Pathol ; : 3009858211043084, 2021 Sep 01.
Article in English | MEDLINE | ID: covidwho-1381204

ABSTRACT

Several animal models have been developed to study the pathophysiology of SARS-CoV-2 infection and to evaluate vaccines and therapeutic agents for this emerging disease. Similar to infection with SARS-CoV-1, infection of Syrian hamsters with SARS-CoV-2 results in moderate respiratory disease involving the airways and lung parenchyma but does not lead to increased mortality. Using a combination of immunohistochemistry and transmission electron microscopy, we showed that the epithelium of the conducting airways of hamsters was the primary target for viral infection within the first 5 days of infection, with little evidence of productive infection of pneumocytes. At 6 days postinfection, antigen was cleared but parenchymal damage persisted, and the major pathological changes resolved by day 14. These findings are similar to those previously reported for hamsters with SARS-CoV-1 infection. In contrast, infection of K18-hACE2 transgenic mice resulted in pneumocyte damage, with viral particles and replication complexes in both type I and type II pneumocytes together with the presence of convoluted or cubic membranes; however, there was no evidence of virus replication in the conducting airways. The Syrian hamster is a useful model for the study of SARS-CoV-2 transmission and vaccination strategies, whereas infection of the K18-hCE2 transgenic mouse results in lethal disease with fatal neuroinvasion but with sparing of conducting airways.

13.
Build Environ ; 198: 107839, 2021 Jul.
Article in English | MEDLINE | ID: covidwho-1184861

ABSTRACT

An outbreak of COVID-19 occurred on the Diamond Princess cruise ship in January and February 2020 in Japan. We analysed information on the cases of infection to infer whether airborne transmission of SARS-CoV-2, the causative agent of COVID-19, had occurred between cabins. We infer from our analysis that most infections in passengers started on 28 January and were completed by 6 February, except in those who shared a cabin with another infected passenger. The distribution of the infected cabins was random, and no spatial cluster of the infected can be identified. We infer that the ship's central air-conditioning system for passenger's cabins did not play a role in SARS-CoV-2 transmission, i.e. airborne transmission did not occur between cabins during the outbreak, suggesting that the sufficient ventilation was provided. We also infer that the ship's cabin drainage system did not play a role. Most transmission appears to have occurred in the public areas of the cruise ship, likely due to crowding and insufficient ventilation in some of these areas.

14.
Phys Chem Chem Phys ; 23(10): 5852-5863, 2021 Mar 14.
Article in English | MEDLINE | ID: covidwho-1125003

ABSTRACT

COVID-19 has recently caused a global health crisis and an effective interventional therapy is urgently needed. Remdesivir is one effective inhibitor for SARS-CoV-2 viral RNA replication. It supersedes other NTP analogues because it not only terminates the polymerization activity of RNA-dependent RNA polymerase (RdRp), but also inhibits the proofreading activity of intrinsic exoribonuclease (ExoN). Even though the static structure of Remdesivir binding to RdRp has been solved and biochemical experiments have suggested it to be a "delayed chain terminator", the underlying molecular mechanisms is not fully understood. Here, we performed all-atom molecular dynamics (MD) simulations with an accumulated simulation time of 24 microseconds to elucidate the inhibitory mechanism of Remdesivir on nucleotide addition and proofreading. We found that when Remdesivir locates at an upstream site in RdRp, the 1'-cyano group experiences electrostatic interactions with a salt bridge (Asp865-Lys593), which subsequently halts translocation. Our findings can supplement the current understanding of the delayed chain termination exerted by Remdesivir and provide an alternative molecular explanation about Remdesivir's inhibitory mechanism. Such inhibition also reduces the likelihood of Remdesivir to be cleaved by ExoN acting on 3'-terminal nucleotides. Furthermore, our study also suggests that Remdesivir's 1'-cyano group can disrupt the cleavage site of ExoN via steric interactions, leading to a further reduction in the cleavage efficiency. Our work provides plausible and novel mechanisms at the molecular level of how Remdesivir inhibits viral RNA replication, and our findings may guide rational design for new treatments of COVID-19 targeting viral replication.


Subject(s)
Adenosine Monophosphate/analogs & derivatives , Alanine/analogs & derivatives , Cyanides/chemistry , Nucleotides/metabolism , RNA-Dependent RNA Polymerase/metabolism , SARS-CoV-2/physiology , Adenosine Monophosphate/chemistry , Adenosine Monophosphate/metabolism , Adenosine Monophosphate/pharmacology , Adenosine Monophosphate/therapeutic use , Alanine/chemistry , Alanine/metabolism , Alanine/pharmacology , Alanine/therapeutic use , COVID-19/drug therapy , COVID-19/pathology , COVID-19/virology , Catalytic Domain , Humans , Molecular Dynamics Simulation , RNA-Dependent RNA Polymerase/antagonists & inhibitors , Ribose/chemistry , SARS-CoV-2/isolation & purification , SARS-CoV-2/metabolism , Static Electricity , Virus Replication/drug effects
16.
J Clin Microbiol ; 59(2)2021 01 21.
Article in English | MEDLINE | ID: covidwho-1043639

ABSTRACT

Surrogate neutralization assays for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that can be done without biosafety level 3 containment and in multiple species are desirable. We evaluate a recently developed surrogate virus neutralization test (sVNT) in comparison to 90% plaque reduction neutralization tests (PRNT90) in human, canine, cat, and hamster sera. With PRNT90 as the reference, sVNT had sensitivity of 98.9% and specificity of 98.8%. Using a panel of immune sera corresponding to other coronaviruses, we confirm the lack of cross-reactivity to other coronaviruses in SARS-CoV-2 sVNT and PRNT90, except for cross-reactivity to SARS-CoV-1 in sVNT.


Subject(s)
COVID-19 Serological Testing/methods , COVID-19/diagnosis , Neutralization Tests/methods , SARS-CoV-2/isolation & purification , Animals , Antibodies, Neutralizing/blood , Antibodies, Viral/blood , COVID-19/blood , COVID-19/pathology , Cats , Cricetinae , Cross Reactions , Dogs , Female , Humans , Immune Sera/immunology , Male , Neutralization Tests/standards , SARS-CoV-2/immunology , Sensitivity and Specificity
17.
Science ; 370(6521): 1208-1214, 2020 12 04.
Article in English | MEDLINE | ID: covidwho-913668

ABSTRACT

We developed a de novo protein design strategy to swiftly engineer decoys for neutralizing pathogens that exploit extracellular host proteins to infect the cell. Our pipeline allowed the design, validation, and optimization of de novo human angiotensin-converting enzyme 2 (hACE2) decoys to neutralize severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The best monovalent decoy, CTC-445.2, bound with low nanomolar affinity and high specificity to the receptor-binding domain (RBD) of the spike protein. Cryo-electron microscopy (cryo-EM) showed that the design is accurate and can simultaneously bind to all three RBDs of a single spike protein. Because the decoy replicates the spike protein target interface in hACE2, it is intrinsically resilient to viral mutational escape. A bivalent decoy, CTC-445.2d, showed ~10-fold improvement in binding. CTC-445.2d potently neutralized SARS-CoV-2 infection of cells in vitro, and a single intranasal prophylactic dose of decoy protected Syrian hamsters from a subsequent lethal SARS-CoV-2 challenge.


Subject(s)
Angiotensin-Converting Enzyme 2/antagonists & inhibitors , Antiviral Agents/pharmacology , COVID-19/drug therapy , Receptors, Virus/antagonists & inhibitors , Recombinant Proteins/pharmacology , SARS-CoV-2/drug effects , Spike Glycoprotein, Coronavirus/antagonists & inhibitors , Animals , Antiviral Agents/chemistry , Antiviral Agents/therapeutic use , Cricetinae , Cryoelectron Microscopy , Directed Molecular Evolution/methods , Protein Binding , Protein Domains , Protein Engineering/methods , Recombinant Proteins/chemistry , Recombinant Proteins/therapeutic use , Spike Glycoprotein, Coronavirus/chemistry
18.
J Hazard Mater ; 402: 123771, 2021 01 15.
Article in English | MEDLINE | ID: covidwho-728695

ABSTRACT

Understanding the transmission mechanism of SARS-CoV-2 is a prerequisite to effective control measures. To investigate the potential modes of SARS-CoV-2 transmission, 21 COVID-19 patients from 12-47 days after symptom onset were recruited. We monitored the release of SARS-CoV-2 from the patients' exhaled breath and systematically investigated environmental contamination of air, public surfaces, personal necessities, and the drainage system. SARS-CoV-2 RNA was detected in 0 of 9 exhaled breath samples, 2 of 8 exhaled breath condensate samples, 1 of 12 bedside air samples, 4 of 132 samples from private surfaces, 0 of 70 samples from frequently touched public surfaces in isolation rooms, and 7 of 23 feces-related air/surface/water samples. The maximum viral RNA concentrations were 1857 copies/m3 in the air, 38 copies/cm2 in sampled surfaces and 3092 copies/mL in sewage/wastewater samples. Our results suggest that nosocomial transmission of SARS-CoV-2 can occur via multiple routes. However, the low detection frequency and limited quantity of viral RNA from the breath and environmental specimens may be related to the reduced viral load of the COVID-19 patients on later days after symptom onset. These findings suggest that the transmission dynamics of SARS-CoV-2 differ from those of SARS-CoV in healthcare settings.


Subject(s)
COVID-19/transmission , Disease Transmission, Infectious/prevention & control , SARS-CoV-2 , Adolescent , Adult , Aged , COVID-19/virology , Cross Infection/prevention & control , Feces/virology , Female , Fomites/virology , Hospitals, University , Humans , Infection Control/methods , Male , Middle Aged , RNA, Viral/analysis , SARS-CoV-2/chemistry , SARS-CoV-2/isolation & purification , Sputum/virology
19.
Sci Total Environ ; 753: 141710, 2021 Jan 20.
Article in English | MEDLINE | ID: covidwho-713250

ABSTRACT

Respiratory and fecal aerosols play confirmed and suspected roles, respectively, in transmitting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). An extensive environmental sampling campaign of both toilet and non-toilet environments was performed in a dedicated hospital building for patients with coronavirus disease 2019 (COVID-19), and the associated environmental factors were analyzed. In total, 107 surface samples, 46 air samples, two exhaled condensate samples, and two expired air samples were collected within and beyond four three-bed isolation rooms. The data of the COVID-19 patients were collected. The building environmental design and the cleaning routines were reviewed. Field measurements of airflow and CO2 concentrations were conducted. The 107 surface samples comprised 37 from toilets, 34 from other surfaces in isolation rooms, and 36 from other surfaces outside the isolation rooms in the hospital. Four of these samples were positive, namely two ward door handles, one bathroom toilet seat cover, and one bathroom door handle. Three were weakly positive, namely one bathroom toilet seat, one bathroom washbasin tap lever, and one bathroom ceiling exhaust louver. Of the 46 air samples, one collected from a corridor was weakly positive. The two exhaled condensate samples and the two expired air samples were negative. The fecal-derived aerosols in patients' toilets contained most of the detected SARS-CoV-2 in the hospital, highlighting the importance of surface and hand hygiene for intervention.


Subject(s)
Bathroom Equipment , Coronavirus Infections , Pandemics , Pneumonia, Viral , Severe Acute Respiratory Syndrome , Betacoronavirus , COVID-19 , Hospitals , Humans , SARS-CoV-2
20.
Nat Med ; 26(6): 981, 2020 06.
Article in English | MEDLINE | ID: covidwho-617429

ABSTRACT

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

SELECTION OF CITATIONS
SEARCH DETAIL